Plant one this spring, and it could reach heights of 10, 20, even 30 feet by summer's end.

Coral Honeysuckle

Coral Honeysuckle

Throughout this perennial's long bloom time, from mid-June through September, its trumpet-shaped blossoms can perfume your entire garden. Coral honeysuckle will twine around anything in its path, scaling a 10- to 15-foot trellis in a single season, and attract hummingbirds as well.

Sweet Autumn Clematis

Sweet Autumn Clematis

Clematis terniflora; Zones 4-9

A very vigorous clematis, this vine doesn't just grow tall (up to 30 feet in a few months); it also grows wide, ensuring full coverage. Consider its tiny white flowers, which bloom in late summer and early fall, a bonus. Oh, and did we mention that the plant tolerates most soil and sun conditions?